青铜器鉴定专家系统中的不确定性推理

讨论了青铜器鉴定专家系统的不确定性推理方法,包括知识的不精确表示,推理规则的不精确表示,组合证据的不精确描述以及推理规则的更新。并将该推理方法应用干文物鉴定领域,成功建立了青铜器鉴定专家系统。     

云推理方法及其在预测中的应用

不确定性推理是当前人工智能研究领域中的一项重要研究内容。云模型实现了定性概念与其定量表示之间的不确定转换,在云模型基础上构建的规则发生器能有效描述用自然语言表示的定性规则,实现不确定性推理。将基于云模型的不确定性推理方法用于预测实际工作环境中电子产品的使用寿命,说明了云推理方法的有效性和实用性。     

基于证据理论的不确定性推理方法及其应用

针对民航无线电管理中遇到的干扰问题以及客观世界中描述客观现象的知识和信息具有不确定性的特点,结合民航无线电干扰查处的实际情况,提出基于一种产生式规则的知识表示方法,以区间确定因子描述不确定性。提出基于Dempster-Shafer证据理论和区间确定因子的不确定性推理方法。进一步根据领域专家经验建立民航无线电干扰查处规则,以基于Dempster-Shafer证据理论和区间确定因子的不确定性推理方法为推理机,给出民航无线电干扰查处专家系统的结构及工作流程,采用C#语言结合MySQL数据库开发民航无线电干扰查处专家系统,并通过案例分析说明该系统的有效性和实用性。     

基于模糊Petri网的三值产生式知识表示及推理

针对传统产生式规则无法进行不确定性知识表示和推理的局限,本文使用三值产生式规则,用-1表示前提、结论和它们之间的不确定性,提出一种基于模糊Petri网的三值产生式知识表示和不确定性推理算法.该算法充分利用推理过程中已得到的中间结论,通过标识和关联矩阵的运算实现高速推理.     

一种基于区间规则的条件证据网络推理决策方法

针对证据网络推理方法无法对区间规则进行表示和推理的问题, 提出一种基于区间规则的条件证据网络推理决策方法. 该方法针对模糊规则的条件概率或信度为不确定区间的情况, 可同时表达不确定性和模糊性; 并将区间不确定规则转化为区间条件信度函数作为证据网络的结点参数, 通过条件推理和证据融合得到条件证据网络中各结点幂集空间中焦元的随机分布作为决策依据. 最后, 通过空中目标态势评估实例, 验证了所提出方法的有效性.

     

产生式规则专家系统的原理与实现

不确定的知识表示与知识推理是专家系统研究和开发的难点。本文利用“目标驱动”方法中控制模块、规则库和事实数据库的操作原理，使用SQL Server2000和Delphi 6．0作为开发平台，通过数据格式和算法的设计构造并实现了一个产生式规则专家系统。该系统实现了不确定性知识表示和知识推理的计算机化，用户只需要为系统提供足够的已知数据，就可以获得专家水平的结论。     

一种新的不确定推理方法

提出了一种基于认知结构的不确定推理方法:采用四值认知结构表达不确定知识,采用定义在认知结构上的双向认知推理结构来处理推理规则的不确定性.介绍的不确定推理方法可以包容精确的概率推理、容忍信息的不确定性、有效地避免推理规则之间的相互关系问题,并且使认知结构最简推理的计算复杂度与推理节点个数成线性关系.     

基于知识Petri网的确定性和不确定性联合推理

知识推理是人工智能的核心领域,旨在研究如何从已知(知识库和推理规则)推理出未知,以帮助智能体做出科学决策.而智能体所处的环境存在不可观性和不确定性,因此知识库通常不仅包含确定性知识,还包含不确定性知识,而且推理过程需要两类知识紧密协作.然而,目前的推理方法无法将两类知识统一表示,常常将两者对应的推理过程割裂进行.基于此,为了实现在统一的模型架构下完成确定性和不确定性联合推理,给出了一种知识Petri网推理方法.首先,定义了一种新的知识Petri网,使其不仅能够描述确定性的知识规范,也可以描述先验概率知识;其次,根据知识Petri网的网结构,给出了一种知识Petri网概率独立剪枝算法,能够指数级地降低不确定性推理的计算复杂性;最后,利用知识Petri网及其概率独立剪枝算法,给出了一种新型推理算法,实现了确定性和不确定性的联合推理,并利用Wumpus世界进行了演示和验证.     

数据缺失的扩展置信规则库推理方法

数据驱动的扩展置信规则库专家系统能够处理含有定量数据或定性知识的不确定性问题.该方法已被广泛地研究和应用,但仍缺乏在不完整数据问题上的研究.鉴于此,针对不完整数据集上的问题,提出一种新的扩展置信规则库专家系统推理方法.首先提出基于析取范式的扩展规则结构,并通过实验讨论了在新的规则结构下,置信规则前提属性参考值个数对推理...     

基于知识的航电设备故障诊断专家系统

为了解决航电设备故障难以诊断的问题,设计一个基于知识的航电设备故障诊断专家系统。该系统中的知识表示形式及与之相配合的基于确定性理论模型的不确定性推理方法,以及基于示例的推理方法可以实现航电设备的故障推理和诊断,其规则的可信度可达到理想的程度。     

Belief rule-base inference methodology using the evidential reasoning Approach-RIMER

In this paper, a generic rule-base inference methodology using the evidential reasoning (RIMER) approach is proposed. Existing knowledge-base structures are first examined, and knowledge representation schemes under uncertainty are then briefly analyzed. Based on this analysis, a new knowledge representation scheme in a rule base is proposed using a belief structure. In this scheme, a rule base is designed with belief degrees embedded in all possible consequents of a rule. Such a rule base is capable of capturing vagueness, incompleteness, and nonlinear causal relationships, while traditional if-then rules can be represented as a special case. Other knowledge representation parameters such as the weights of both attributes and rules are also investigated in the scheme. In an established rule base, an input to an antecedent attribute is transformed into a belief distribution. Subsequently, inference in such a rule base is implemented using the evidential reasoning (ER) approach. The scheme is further extended to inference in hierarchical rule bases. A numerical study is provided to illustrate the potential applications of the proposed methodology.     

A new belief rule base knowledge representation scheme and inference methodology using the evidential reasoning rule for evidence combination

In this paper, we extend the original belief rule-base inference methodology using the evidential reasoning approach by i) introducing generalised belief rules as knowledge representation scheme, and ii) using the evidential reasoning rule for evidence combination in the rule-base inference methodology instead of the evidential reasoning approach. The result is a new rule-base inference methodology which is able to handle a combination of various types of uncertainty.Generalised belief rules are an extension of traditional rules where each consequent of a generalised belief rule is a belief distribution defined on the power set of propositions, or possible outcomes, that are assumed to be collectively exhaustive and mutually exclusive. This novel extension allows any combination of certain, uncertain, interval, partial or incomplete judgements to be represented as rule-based knowledge. It is shown that traditional IF-THEN rules, probabilistic IF-THEN rules, and interval rules are all special cases of the new generalised belief rules.The rule-base inference methodology has been updated to enable inference within generalised belief rule bases. The evidential reasoning rule for evidence combination is used for the aggregation of belief distributions of rule consequents.     

Applying a belief rule-base inference methodology to a guideline-based clinical decision support system

Abstract: A critical issue in the clinical decision support system (CDSS) research area is how to represent and reason with both uncertain medical domain knowledge and clinical symptoms to arrive at accurate conclusions. Although a number of methods and tools have been developed in the past two decades for modelling clinical guidelines, few of those modelling methods have capabilities of handling the uncertainties that exist in almost every stage of a clinical decision-making process. This paper describes how to apply a recently developed generic rule-base inference methodology using the evidential reasoning approach (RIMER) to model clinical guidelines and the clinical inference process in a CDSS. In RIMER, a rule base is designed with belief degrees embedded in all possible consequents of a rule. Such a rule base is capable of capturing vagueness, incompleteness and non-linear causal relationships, while traditional IF–THEN rules can be represented as a special case. Inference in such a rule base is implemented using the evidential reasoning approach which has the capability of handling different types and degrees of uncertainty in both medical domain knowledge and clinical symptoms. A case study demonstrates that employing RIMER in developing a guideline-based CDSS is a valid novel approach.     

基于证据推理和第3 代前景理论的不确定性多属性决策方法

针对多状态不确定性多属性决策问题, 建立基于证据推理和第3 代前景理论的决策方法. 首先, 给出不确定性知识表示方法—– 确定因子结构及其构造方法; 然后, 将第3 代前景理论构造价值函数和确定权重函数引入决策方法中, 得到每个方案在各属性下的前景价值; 进一步, 根据证据推理方法对前景价值进行信息融合得到各方案的合成前景价值, 并依据合成前景价值对方案进行排序; 最后, 通过算例验证了所提出方法的可行性和有效性.

     

基于规则推理网络的分类模型

为了缓解神经网络的“黑盒子”机制引起的算法可解释性低的问题,基于使用证据推理算法的置信规则库推理方法(以下简称RIMER)提出了一个规则推理网络模型.该模型通过RIMER中的置信规则和推理机制提高网络的可解释性.首先证明了基于证据推理的推理函数是可偏导的,保证了算法的可行性;然后,给出了规则推理网络的网络框架和学习算法,利用RIMER中的推理过程作为规则推理网络的前馈过程,以保证网络的可解释性;使用梯度下降法调整规则库中的参数以建立更合理的置信规则库,为了降低学习复杂度,提出了“伪梯度”的概念;最后,通过分类对比实验,分析了所提算法在精确度和可解释性上的优势.实验结果表明,当训练数据集规模较小时,规则推理网络的表现良好,当训练数据规模扩大时,规则推理网络也能达到令人满意的结果.     

Inference analysis and adaptive training for belief rule based systems

Belief rule base (BRB) systems are an extension of traditional IF-THEN rule based systems and capable of capturing complicated nonlinear causal relationships between antecedent attributes and consequents. In a BRB system, various types of information with uncertainties can be represented using belief structures, and a belief rule is designed with belief degrees embedded in its possible consequents. For a set of inputs to antecedent attributes, inference in BRB is implemented using the evidential reasoning (ER) approach. In this paper, the inference mechanism of the ER algorithm is analyzed first and its patterns of monotonic inference and nonlinear approximation are revealed. For a practical BRB system, it is difficult to determine its parameters accurately by using only experts’ subjective knowledge. Moreover, the appropriate adjustment of the parameters of a BRB system using available historical data can lead to significant improvement on its prediction performance. In this paper, a training data selection scheme and an adaptive training method are developed for updating BRB parameters. Finally, numerical studies on a multi-modal function and a practical pipeline leak detection problem are conducted to illustrate the functionality of BRB systems and validate the performance of the adaptive training technique.     

基于可拓规则的故障诊断专家系统推理机的研究

针对传统产生式规则在知识表示、匹配冲突等方面存在的局限,提出了一种将可拓规则用于故障诊断专家系统推理机的方法;该方法重点研究了可拓规则的匹配原理和可拓推理机算法思想,提出了匹配度计算方法并用来计算故障条件与规则前件的匹配度;根据研究表明,利用可拓规则进行推理,不仅在知识表示上比传统产生式规则推理有所提高,而且还解决了传统专家系统容易出现匹配冲突等问题;最后以AMU故障推理为例,说明可拓推理机具有推理速度快、效率高等优点,取得了较好的推理效果.     

基于数据库的燃煤锅炉事故诊断专家系统的设计与实现

采用MS SQL Server7．0设计知识库，Visual Basic 6．0编程实现了燃煤锅炉事故诊断专家系统。本系统知识表示采用了基于概率逻辑的产生式规则形式，并用数据库的方法存储管理知识库。推理机采用规则值的方法，并应用主观Bayes理论建立了不确定性推理模型。实现了一种较为理想的不精确推理。